Carburetor for recovery and utilization of fuel tank vapors



April 18, 1967 D. E. TUTCH 3,314,665

CARBURETOR FOR RECOVERY AND UTILIZATION OF FUEL TANK VAPORS Filed Sept. 28, 1965 MANIFOLD INVENTOR DA VID E. TUT'CH ATT'Y 50 INTAKE 73 United States Patent 3,314,665 CARBURETOR FOR RECOVERY AND UTILIZA. TION OF FUEL TANK VAPORS David E. Tutch, Lynd, Minn., assignor to International Harvester Company, Chicago, 11]., a corporation of Delaware Filed Sept. 28, 1965, Ser. No. 490,887 5 Claims. (Cl. 261-160) This invention relates to a device for utilizing fuel tank vapors in an internal combustion engine fuel and air indu-ction system, and more particularly relates to a carburetor including means for recovering, condensing and utilizing fuel tank vapors.

Considerable attention has been directed in past years to the problem of stopping pollutive hydrocarbon emissions from internal combustion engine vehicles. While attention has been centered in the past primarily on exhaust fumes, more recently attention has been directed to fuel vapors escaping from the external vents of the vehicle fuel tank. In addition to the problem of smog associated with fuel vapor emissions, there is an allied problem of increased cost of operation. This latter problem becomes relatively more acute where industrial or agricultural vehicles are being used. Here, the fuel tank may be exposed conventionally to the direct rays of the sun for long continuous periods of use resulting in increased fuel temperature and extra costs due to the escape of such fuel vapors to the atmosphere.

The present invention provides a means of utilizing fuel tank vapors by condensing fuel vapors from the fuel tank to liquid form and delivering this condensed fuel in metered amounts to the engine. This is accomplished by routing fuel tank vapors to a low temperature area of the carburetor in the vicinity of the venturi where a heat sink or low temperature zone is produced due to vaporization of fuel in this area.

Thus, an object of the invention is to provide a device for recovering and utilizing in a carburetor fuel tank vapors which would otherwise be vented to the atmosphere.

Another object of the invention is to utilize fuel tank vapors which would otherwise escape to the atmosphere by directing such vapors to the carburetor and by providing means for condensing such vapors in the carburetor and directing them in liquid form to the carburetor float bowl for delivery to the engine intake manifold along with other fuel metered thereto by the carburetor.

Yet another object of the invention is to provide an improved carburetor suitable for use with conventional internal combustion engine fuel and air induction systems to condense and utilize fuel vapors emanating from the fuel tank during and immediately after operation of the engine.

These and other objects of the invention will become clear upon consideration of the following detailed description and associated drawing, wherein is shown a schematic view of a fuel and air induction system of an internalTo'mbustion engine including a sectional view in side elevation of a carburetor.

Referring to the drawing, there is shown a carburetor of the updraft type designated generally by the numeral and connected communicatively in a fuel and air induct-ion system for an internal combustion engine 12. The system include-s a fuel tank 14 having a top 16 and a bottom 18, an inlet 20 and a head space 22 above the level of fuel 23 in the tank, the fuel tank 14 being connected communicatively by a first conduit 26 to an engine-operated fuel pump 28 supplying fuel to a second conduit 30 leading to the carburetor.

The carburetor 10 includes a body 32 having an air intake passage 34 connected communicatively to an airfuel outlet or exhaust passage 36; and a float bowl or fuel reservoir 38 to receive fuel from the fuel tank through conduits 26, 30 and to maintain it at a predetermined level within the bowl 38.

A choke valve 40 is conventionally positioned in the air intake passage 34 to regulate the flow of air therethrough. The air-fuel outlet passage 36 is connected communicatively to an intake manifold 42 of the engine 12, the outlet passage 36 having a throttle valve 44 rotatably positioned therein to regulate the flow of an air-fuel mixture to the intake manifold. The outlet passage 36 has a venturi portion 46 of relatively smaller inner diameter and crosssectional area than the outlet passage 36 positioned therein between its one end proximate the intake passsage 34 and its other end proximate the throttle valve 44.

The carburetor float bowl 38 includes an inlet 48 and an outlet 50 having an adjustable orifice 52 therein, the orifice 52 being adjustable by means of a fuel adjusting needle 54 mounted within the carburetor float bowl 38 to adjust the flow of fuel from the float bowl through the orifice opening 52. A float 56 and needle valve 58 secured thereto is pivotally mounted within the bowl as at 59 to open and block a flow of fuel through inlet 48 into the bowl to maintain a predetermined level of fuel within the bowl.

The carburetor also include-s a fuel delivery nozzle 68 having an inlet end 62 and a discharge end 64, the inlet end 62 being communicatively connected to the float bowl by means of orifice 52 to receive fuel therefrom, with the discharge end 64 conventionally positioned in the air-fuel outlet passageway 36 proximate the venturi 46. As is well known, with the engine 12 operating, a flow of air upwardly from passageway 34 through the restriction provided by the venturi 46 causes a flow of fuel from the nozzle 60 into the venturi 46 where it is vaporized and mixed with intake air flowing through the passage provided by the venturi.

In accordance with the invention, carburetor condensation means are provided to receive and condense fuel vapors received from the fuel tank, the condensation means comprising a circumferentially extending condensation passageway or chamber 68 provided in the carburetor and being radially spaced between the air-fuel outlet passage 36 and the venturi portion 46. The condensation passageway 68 is provided in an area radially outwardly and about the venturi in an area where a heat sink or place of low temperature suflicient to condense fuel vapor has been found to exist due to vaporization of fuel in this area. Condensation passageway 68 has an upper end 78 proximate the throttle 44 and a lower end 72 proximate the float bowl. As should be clear, the heat sink or low temperature area may extend upwardly, as viewed in the drawing, toward the throttle 44 and hence the upper end 78 of the condensation passageway may extend into the carburetor body 32 above the venturi 46 between the venturi and the throttle 44.. The lower end 72 of the venturi is positioned relatively higher than the fuel bowl 38 to permit a flow of condensed fuel from the condensation passageway 68 through an outlet 74 proximate the lower end 72 into the float bowl. The condensation passageway 68 includes an inlet 76 at its upper end connected communicatively by a third conduit 78 to the head space 22 of the fuel tank above the level of fuel in the fuel tank, the conduit 78 permitting a flow of fuel vapors from head space 22 to the condensation passageway 68.

Means are provided in the float bowl 38 to open and close the flow of condensed 'fuel vapor from condensation passageway 68 to the fiuid bowl and comprises a float 88 and needle valve 82 mounted thereon and pivotally secured within the fluid bowl as at 84 to open and block a flow of condensed fuel from condensation passageway 68 when the level of fuel within the bowl 38 has reached a predetermined level relatively higher than the level at which float 56 and needle valve 58 are set to close the flow of fuel from the line 30.

Having now described the invention, its operation should be clear. During operation of an associated vehicle and especially where the fuel tank is exposed to high temperatures for relatively long periods of time, considerable fuel vapor which is generated within the fuel tank is vented conventionally to the atmosphere resulting in loss of considerable fuel. To utilize this fuel vapor which would otherwise be wasted, a carburetor condensation passageway is provided in the area about the venturi where a relatively lower temperature sufficient to con- 'dense fuel vapor has been found to occur. Upon operation of the engine, vaporization of fuel within the venturi causes a considerable drop in temperature about the venturi and for a distance between the venturi and the throttle valve. This lower temperature causes fuel vapor in condensation passageway 68 to condense and effects a flow of fuel vapor from the fuel tank to the carburetor condensation passageway where it is similarly cooled and condensed. The condensed vapor flows from the condensation passageway by the force of gravity into float bowl 38 where float valve 80, 82 are set to permit a flow of such condensed vapor to the float bowl almost continuously during operation of the engine and for a period of time thereafter.

Fuel vapor condensed in the condensation passageway 68 flows through opening 74- to the float bowl 38 when it mixes with other fuel conventionally supplied by the pump 28 from the fuel tank. The fuel flow from the bowl 38 is in .metered amounts through orifice 52 to the nozzle 60 where it is drawn into the venturi portion, vaporized and carried through passageway 36 to the intake manifold 42 of the engine 12.

Upon stopping operation of the engine, the condensation float 80 and valve 82 are set to permit continued condensation of fuel vapor from the fuel tank since the venturi area remains cool for a period of time after stopping engine operation. As the level of fluid within the fuel bowl reaches a predetermined point, the float and needle valve 56, 58 block a further flow of fuel from line 30. However, at this time, float and needle valve 80, 82 are still open to permit a flow of condensed vapor to the fluid bowl. Thus vapor from the fuel tank flowing to the condensation passageway 68 continues to be condensed and to flow to the float bowl until the valve 82 blocks off the flow of fuel thereto.

Since modifications of the detail of the structure illustrated are contemplated, the invention should be limited only by the scope of the appended claims.

The invention is claimed as follows:

1. A carburetor for an internal combustion engine fuel and air induction system, said system including a fuel tank to contain fuel and an intake manifold to distribute fuel-air mixtures from said carburetor to said engine, said carburetor comprising:

.(a) a body having an air intake passage and an airfuel outlet passage communicatively connected there to, said outlet passage being communicatively connected to said engine intake manifold,

(b) a venturi portion positioned within outlet passage,

(c) a carburetor fuel reservoir connected communicatively to said fuel tank to maintain fuel received from said fuel tank at a substantially constant level therein,

(d) a fuel delivery nozzle secured within said carburetor, said nozzle having an inlet end and a discharge end, said inlet end being communicatively connected to said fuel reservoir, said discharge end being positioned within said venturi portion,

(c) said venturi being spaced from said body to prosaid air-fuel vide a condensation passageway between said body and said venturi,

(f) means communicatively connecting said fuel tank at a location above a level of fuel therein with said condensation passageway at an upper portion thereof,

(g) means conmmunicatively connecting said condensation passageway at a lower portion thereof with said fuel reservoir,

(h) valve means within said fuel reservoir to stop a flow of fuel from said fuel tank thereto when the level of fuel within said fuel reservoir has reached a first predetermined level.

2. The carburetor of claim 1 including second valve means to stop a flow of fuel from said condensation passageway when the level of fuel .within said fuel reservoir has reached a second predetermined level, said second predetermined level being relatively higher than said first predetermined level.

3. A carburetor for an internal combustion engine fuel and air induction system, said system including a fuel tank having a top and a bottom, an engine intake manifold to distribute fuel-air mixture from said carburetor to said engine, a fuel pump to provide a flow of fuel from said fuel tank to said carburetor, said carburetor comprising:

(a) a body having an air intake passage and an airfuel outlet passage communicatively connected thereto, said outlet passage having a predetermined inner diameter and being communicatively connected to said engine intake manifold to deliver a mixture of fuel and air thereto,

('b) a venturi portion positioned within said air-fuel outlet passage,

(c) a fuel reservoir to receive fuel from said fuel tank and to :maintain said fuel at a relatively constant level in said fuel reservoir, said fuel reservoir having an upper portion and a lower portion, an inlet at an upper portion of said reservoir communicatively connected to said fuel tank, said fuel pump being connected communicatively between said fuel tank and said fuel reservoir inlet, said reservoir having an outlet proximate said lower portion,

(d) a fuel delivery nozzle secured within said carburetor, said nozzle having an inlet end and a discharge end, said inlet end being communicatively connected to said fuel reservoir outlet, said discharge end being positioned in said carburetor outlet passage proximate said venturi portion,

(c) said venturi being spaced from said body to provide a condensation passageway between said body and said venturi, said condensation passage having first and second openings therein positioned respectively at upper and lower portions thereof,-

(f) means communicatively connecting said fuel tank at a position above the level of fuel therein with said first opening of said condensation passage,

(g) means communicatively connecting said second opening of said condensation passage with said fuel reservoir to permit a flow of fuel to said fuel reservoir,

(h) first valve means within said fuel reservoir to stop a flow of fuel from said fuel tank thereto when the level of fuel within said fuel reservoir has reached a first predetermined level,

(i) and second valve means within said fuel reservoir to stop a flow of fuel from said condensation passage when the level of fuel within said fuel reservoir has reached a second predetermined level, said second predetermined level being relatively higher than said first predetermined level,

whereby during operation of said engine and carburetor, a flow of air and vaporized fuel from said air intake passage through said venturi portion creates a drop of temperature thereabout tending to condense fuel vapor from said fuel tank circulating in said condensation passageway to form condensed fuel vapor, said condensed fuel vapor moving from said condensation passageway to said fuel reservoir to mix with said fuel from said fuel tank in said reservoir.

4. In an air and fuel charging device for an internal combustion engine fuel and air induction system, said system including an engine intake manifold and a fuel tank to hold fuel, said tank having a head space above the level of fuel therein and means to permit fuel flow to said charging device, said air and fuel charging device including a body, an air intake passage, an air-fuel exhaust passage, a venturi portion positioned in said exhaust passage providing a passageway therethrough, said passageway having a portion thereof having a relatively smaller diameter than the diameter of the balance of said exhaust passage, a throttle valve positioned within said discharge passage, said throttle valve being rotatably positioned to vary the flow of an air-fuel mixture to said intake manifold of said engine, said charging device having a float chamber including first valve means therein to stop a flow of fuel thereto from said fuel tank at a predetermined level of fuel in said float chamber, a fuel delivering nozzle Within said carburetor having an inlet opening and a discharge opening, said inlet opening being communicatively connected to said float chamber proximate the lowest level of said float chamber, said discharge opening of said nozzle being positioned proximate said venturi portion, the combination therewith comprising:

(a) said venturi being spaced from said body to define a vapor condensation passageway between said body and said venturi, said vapor passageway having an inlet opening and an outlet opening, said inlet opening being at an upper portion thereof, said outlet opening being at a lower portion thereof, said inlet opening being above the level of said float chamber, said vapor passageway inlet opening being communicatively connected to said fuel tank, said outlet opening being communicatively connected to said float chamber above the level of fuel therein, whereby upon operation of said engine vaporization of fuel from said nozzle takes place within said venturi portion effecting a cooling and condensation of vapor within said vapor passageway, said condensed vapor flowing into said float chamber,

(b) and second valve means within said float chamber to stop the flow of fuel thereto from said vapor passageway at a level of fuel therein relatively higher than the predetermined level of fuel maintained by said first valve means.

5. In a carburetor for an engine fuel and air induction system, said system including an intake manifold and a fuel tank to hold fuel, said tank having a head space above the level of fuel therein and means to permit fuel flow to said carburetor, said carburetor including a body, an air intake passage, an air-fuel outlet passage communicating with said intake manifold, a venturi passage secured within said outlet passage, a throttle valve rotatably positioned in said air-fuel outlet passage, said carburetor having a float chamber to contain fuel from said fuel tank, valve means to stop a flow of fuel from said fuel tank to said float chamber at a predetermined level, a fuel delivering nozzle within said carburetor having an inlet opening and a discharge opening, said inlet opening being communicatively connected to said float chamber, said discharge opening of said nozzle being positioned proximate said venturi, the combination therewith comprising:

(a) said venturi being spaced from said body to define a vapor condensation passageway in said carburetor between said body and said venturi, said vapor passageway having an inlet opening and an outlet opening, said inlet opening being at an upper portion thereof, said outlet opening being at a lower location thereof proximate said float chamber, said venturi portion extending for a distance between said float chamber and said throttle valve, said inlet opening being communicatively connected to said fuel tank head space, said outlet opening being communicatively connected to said float chamber at a location above the level of fuel therein whereby upon operation of said engine, vaporization of fuel within said outlet passage of said carburetor creates a drop in temperature about said venturi to condense fuel vapor in said vapor passageway,

(b) and means within said float chamber to stop the flow of fuel from said vapor passageway thereto at a predetermined level of fuel therein.

References Cited by theExaminer UNITED STATES PATENTS 1,889,922 12/1932 Justheim 26l--72 2,701,709 2/ 1955 Brunner 261-72 X 2,801,623 8/1957 Stearns 261-72 X 2,894,736 7/1959 Wentworth 2-61--72 HARRY B. THORNTON, Primary Examiner R. WEAVER, Assistant Examiner. 

1. A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE FUEL AND AIR INDUCTION SYSTEM, SAID SYSTEM INCLUDING A FUEL TANK TO CONTAIN FUEL AND AN INTAKE MANIFOLD TO DISTRIBUTE FUEL-AIR MIXTURES FROM SAID CARBURETOR TO SAID ENGINE, SAID CARBURETOR COMPRISING: (A) A BODY HAVING AN AIR INTAKE PASSAGE AND AN AIRFUEL OUTLET PASSAGE COMMUNICATIVELY CONNECTED THERETO, SAID OUTLET PASSAGE BEING COMMUNICATIVELY CONNECTED TO SAID ENGINE INTAKE MANIFOLD, (B) A VENTURI PORTION POSITIONED WITHIN SAID AIR-FUEL OUTLET PASSAGE, (C) A CARBURETOR FUEL RESERVOIR CONNECTED COMMUNICATIVELY TO SAID FUEL TANK TO MAINTAIN FUEL RECEIVED FROM SAID FUEL TANK AT A SUBSTANTIALLY CONSTANT LEVEL THEREIN, (D) A FUEL DELIVERY NOZZLE SECURED WITHIN SAID CARBURETOR, SAID NOZZLE HAVING AN INLET END AND A DISCHARGE END, SAID INLET END BEING COMMUNICATIVELY CONNECTED TO SAID FUEL RESERVOIR, SAID DISCHARGE END BEING POSITIONED WITHIN SAID VENTURI PORTION, 